Monthly Notices is one of the three largest general primary astronomical research publications. It is an international journal, published by the Royal Astronomical Society. This article 1 describes its publication policy and practice.

Monthly Notices of the Royal Astronomical Society

Computational Hydrodynamics To Grid or Not to Grid: A Primer on Hydrocodes Equations of Stellar Structure A Touch of Hydrodynamics Grid-Based Methods: The Realm of Finite Differences Gridless Methods: Smoothed-Particle Hydrodynamics Building a 1D Hydrodynamic Code Code Validation and Verification Nuclear Physics Nuclear Prelude: Abundances, Masses, and Binding Energies Nuclear Fusion Nuclear Interactions Stellar Evolution in a Nutshell: H- to Si-Burning Cosmochemistry and Presolar Grains Meteorites and Stellar Astrophysics Grain Formation and Growth The Stardust Market Experimental Techniques and Instruments Classical and Recurrent Novae Stellae Novae: Beacons in the Ocean of Night Classical and Recurrent Novae: The Big Picture Designing a Nova Outburst Nova Nuclear Symphony Nova Light Curve Observational Constraints Type Ia Supernovae Historical Supernovae Spectroscopy of Supernovae Light Curves: Supernova Pyrotechnics Progenitors Blowing Up Stars in the Laptop: The Modeling of Type Ia Supernovae X-Ray Bursts and Superbursts Discovery of X-Ray Bursts Observational Constraints A Spark to a Flame: Outlining the Explosion Mechanism Superbursts Core-Collapse Supernovae SN 1987A Observations of Core-Collapse Supernovae: Spectra and Light Curves Core-Collapse Supernovae: Evolution beyond Core Silicon Burning and Explosion Nucleosynthesis Observational Constraints Supernovae, Neutron Star Mergers, and the Origin of Gamma-Ray Bursts Appendix A: Henyey Method for Arbitrary Hydrodynamic Problems Appendix B: Computer Program for the Free-Fall Collapse Problem Exercises appear at the end of each chapter.

Stellar Explosions: Hydrodynamics and Nucleosynthesis


 Nuclear astrophysics is a field at the intersection of nuclear physics and astrophysics, which seeks to understand the nuclear engines of astronomical objects and the origin of the chemical elements. This white paper summarizes progress and status of the field, the new open questions that have emerged, and the tremendous scientific opportunities that have opened up with major advances in capabilities across an ever growing number of disciplines and subfields that need to be integrated. We take a holistic view of the field discussing the unique challenges and opportunities in nuclear astrophysics in regards to science, diversity, education, and the interdisciplinarity and breadth of the field. Clearly nuclear astrophysics is a dynamic field with a bright future that is entering a new era of discovery opportunities.

Horizons: nuclear astrophysics in the 2020s and beyond

At temperatures below 0.1 GK, the $^{19}\mathrm{F}(p,\ensuremath{\gamma})^{20}\mathrm{Ne}$ reaction is the only breakout path out of the CNO cycle. Experimental studies of this reaction are challenging from a technical perspective due to copious $\ensuremath{\gamma}$-ray background from the far stronger $^{19}\mathrm{F}(p,\ensuremath{\alpha})^{16}\mathrm{O}$ reaction channel. Here, we present the first inverse kinematics study of the $^{19}\mathrm{F}(p,\ensuremath{\gamma})^{20}\mathrm{Ne}$ reaction, in which we measure the strength of the 323-keV resonance. We find a strength value of $\ensuremath{\omega}\ensuremath{\gamma}=3.{3}_{\ensuremath{-}0.9}^{+1.1}$ meV, which is a factor of two larger than the most recent previous study. The discrepancy is likely the result of a direct to ground state transition which previous studies were not sensitive to. We also observe the transition to the first ${2}^{\ensuremath{-}}$ state, which has not been observed for this resonance in previous studies. A new thermonuclear reaction rate is calculated and compared with the literature.

New measurement of the E c.m. = 323 keV resonance in the F 19 ( p , γ ) Ne 20 reaction

The efficiency of the slow neutron-capture process in massive stars is strongly influenced by neutron-capture reactions on light elements. At low metallicity, $^{16}$O is an important neutron absorber, but the effectiveness of $^{16}$O as a light-element neutron poison is modified by competition between subsequent $^{17}$O$(\alpha,n)^{20}$Ne and $^{17}$O$(\alpha,\gamma)^{21}$Ne reactions. The strengths of key $^{17}$O$(\alpha,\gamma)^{21}$Ne resonances within the Gamow window for core helium burning in massive stars are not well constrained by experiment. This work presents more precise measurements of resonances in the energy range $E_{c.m.} = 612 - 1319$ keV. We extract resonance strengths of $\omega\gamma_{638} = 4.85\pm0.79$ $\mu$eV, $\omega\gamma_{721} = 13.0^{+3.3}_{-2.4}$ $\mu$eV, $\omega\gamma_{814} = 7.72\pm0.55$ meV and $\omega\gamma_{1318} = 136\pm 13$ meV, for resonances at $E_{c.m.} =$ 638, 721, 814 and 1318 keV, respectively. We also report an upper limit for the 612 keV resonance of $\omega\gamma<140$ neV ($95\%$ c.l.), which effectively rules out any significant contribution from this resonance to the reaction rate. From this work, a new $^{17}$O$(\alpha,\gamma)^{21}$Ne thermonuclear reaction rate is calculated and compared to the literature. The effect of present uncertainties in the $^{17}$O$(\alpha,\gamma)^{21}$Ne reaction rate on weak s-process yields are then explored using post-processing calculations based on a rotating $20M_{\odot}$ low-metallicity massive star. The resulting $^{17}$O$(\alpha,\gamma)^{21}$Ne reaction rate is lower with respect to the pre-existing literature and found to enhance weak s-process yields in rotating massive star models. 

/pdf/constraints-on-key-mml-math-xmlns-mml-http-www-w3-org-1998-1i697mch.pdf

Constraints on key 
<mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML"><mml:mrow><mml:mmultiscripts><mml:mi mathvariant="normal">O</mml:mi><mml:mprescripts /><mml:none /><mml:mn>17</mml:mn></mml:mmultiscripts><mml:mo>(</mml:mo><mml:mi>α</mml:mi><mml:mo>,</mml:mo><mml:mi>γ</mml:mi><mml:mo>)</mm

http://digital.csic.es/bitstream/10261/236891/1/firstemp.pdf

First inverse kinematics measurement of key resonances in the 22Ne(p,γ)23Na reaction at stellar temperatures

An in-depth characterization of the TACTIC detector was performed using data from a 148Gd alpha source and some test runs with a stable ion beam. The detector is an active target time-projection chamber with a blind central region for maximizing beam tolerance and GEM-based electron amplification, equipped with a modern digitizing data acquisition system allowing the recording of full signals. The system was developed to study the reaction 8Li(α,n)11B, which is important for bridging the mass 8 gap in scenarios of low 4He density like Inhomogeneous Big Bang Nucleosynthesis and the production of r-process seeds in supernovae. Both energy resolution and tracking accuracy were found to agree with theoretical predictions and Geant4 simulations. The 8Li beam rate capability of the system is predicted to be of the order of 105s-1, several orders of magnitude higher than most previous measurements of the same reaction, while still maintaining a high detection efficiency of 70% to 80 %.

http://iopscience.iop.org/article/10.1088/1742-6596/940/1/012048/pdf

TACTIC : The TRIUMF Annular Chamber for Tracking and Identification of Charged particles

Background: Globular clusters are known to exhibit anomalous abundance trends such as the sodium-oxygen anticorrelation. This trend is thought to arise via pollution of the cluster interstellar medium from a previous generation of stars. Intermediate-mass asymptotic giant branch stars undergoing hot bottom burning (HBB) are a prime candidate for producing sodium-rich oxygen-poor material, and then expelling this material via strong stellar winds. The amount of $^{23}\mathrm{Na}$ produced in this environment has been shown to be sensitive to uncertainties in the $^{22}\mathrm{Ne}(p,\ensuremath{\gamma})^{23}\mathrm{Na}$ reaction rate. The $^{22}\mathrm{Ne}(p,\ensuremath{\gamma})^{23}\mathrm{Na}$ reaction is also activated in classical nova nucleosynthesis, strongly influencing predicted isotopic abundance ratios in the Na-Al region. Therefore, improved nuclear physics uncertainties for this reaction rate are of critical importance for the identification and classification of pre-solar grains produced by classical novae.Purpose: At temperatures relevant for both HBB in AGB stars and classical nova nucleosynthesis, the $^{22}\mathrm{Ne}(p,\ensuremath{\gamma})^{23}\mathrm{Na}$ reaction rate is dominated by narrow resonances, with additional contribution from direct capture. This study presents new strength values for seven resonances, as well as a study of direct capture.Method: The experiment was performed in inverse kinematics by impinging an intense isotopically pure beam of $^{22}\mathrm{Ne}$ onto a windowless ${\mathrm{H}}_{2}$ gas target. The $^{23}\mathrm{Na}$ recoils and prompt $\ensuremath{\gamma}$ rays were detected in coincidence using a recoil mass separator coupled to a $4\ensuremath{\pi}$ bismuth-germanate scintillator array surrounding the target.Results: For the low-energy resonances, located at center of mass energies of 149, 181, and 248 keV, we recover stength values of $\ensuremath{\omega}{\ensuremath{\gamma}}_{149}=0.{17}_{\ensuremath{-}0.04}^{+0.05}, \ensuremath{\omega}{\ensuremath{\gamma}}_{181}=2.2\ifmmode\pm\else\textpm\fi{}0.4$, and $\ensuremath{\omega}{\ensuremath{\gamma}}_{248}=8.2\ifmmode\pm\else\textpm\fi{}0.7 \ensuremath{\mu}\text{eV}$, respectively. These results are in broad agreement with recent studies performed by the LUNA and TUNL groups. However, for the important reference resonance at 458 keV we obtain a strength value of $\ensuremath{\omega}{\ensuremath{\gamma}}_{458}=0.44\ifmmode\pm\else\textpm\fi{}0.02$ eV, which is significantly lower than recently reported values. This is the first time that this resonance has been studied completely independently from other resonance strengths. For the 632-keV resonance we recover a strength value of $\ensuremath{\omega}{\ensuremath{\gamma}}_{632}=0.48\ifmmode\pm\else\textpm\fi{}0.02$ eV, which is an order of magnitude higher than a recent study. For reference resonances at 610- and 1222-keV, our strength values are in agreement with the literature. In the case of direct capture, we recover an $S$ factor of 60 keV b, consistent with prior forward kinematics experiments.Conclusions: In summary, we have performed the first direct measurement of $^{22}\mathrm{Ne}(p,\ensuremath{\gamma})^{23}\mathrm{Na}$ in inverse kinematics. Our results are in broad agreement with the literature, with the notable exception of the 458-keV resonance, for which we obtain a lower strength value. We assessed the impact of the present reaction rate in reference to a variety of astrophysical environments, including AGB stars and classical novae. Production of $^{23}\mathrm{Na}$ in AGB stars is minimally influenced by the factor of 4 increase in the present rate compared to the STARLIB-2013 compilation. The present rate does however impact upon the production of nuclei in the Ne-Al region for classical novae, with dramatically improved uncertainties in the predicted isotopic abundances present in the novae ejecta.

/pdf/first-inverse-kinematics-study-of-the-22-ne-p-g-23-na-4p3h2be1nt.pdf

First inverse kinematics study of the $^{22}$Ne$(p,γ)^{23}$Na reaction and its role in AGB star and classical nova nucleosynthesis

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First inverse kinematics measurement of key resonances in the 22Ne(p,γ)23Na reaction at stellar temperatures

TACTIC : The TRIUMF Annular Chamber for Tracking and Identification of Charged particles

First inverse kinematics study of the $^{22}$Ne$(p,γ)^{23}$Na reaction and its role in AGB star and classical nova nucleosynthesis